Everyone is wired different and see things in different ways...and I believe it all depends on your up bringing.
As a 36yr old man, wifey and I have 4 kids (18, 14, 13, 9 year olds). All my kids were made when I was under 30 yrs old. Was it tough ? Yeah...its supposed to be. But the experience was only rough with the 1st kid. I was young and would always be out chillin with my boys for the first couple of years. I then hit a wall of guilt....
My pops was a piece of shyt and bounced out of my life early. I took a step back and realized that I was being just like him. Made me realize that I don't want none of my kids to grow up fatherless like me, so I made the life change of living life for what was best for my family and not "me". Wifey understood me wanting to chill with my boys (I'm sure it irritated her inside), but I made the decision to limit shyt and spend most of my time with wifey and my seed.
I know that decision is what made my relationship solid (thus the 4 kids). Looking out for one another and the best interest of the kids is what makes the relationship better. Honesty and communication is key.
Not to mention. After 4 kids, wifey is still 115 lbs. But a huge part of that was her working out daily, with me or me making the sacrifice to watch the kids while she works out.